European Patent Document No. EP 534 579 A2 discloses a plate clamping device, in which the form cylinder has a cylinder groove running in the axial direction, one edge of which carries the leading flange of the plate. Furthermore, the cylinder groove contains a rotatable spindle, to which U-shaped leaf springs are mounted across the width of the form cylinder. One leg of the leaf springs is bent into a hook shape and engages with and grips, when the spindle is turned, the correspondingly hook-shaped trailing flange of the plate. The other leg of the springs presses the leading flange of the plate against the wall of the cylinder groove. In this device, however, the leading flange of the plate is not held securely in place on the wall of the cylinder groove.